ARCHIVES available in the search window on the header banner. I put "SeaFoam generator" in there but couldn't find the same thing I was talking about...although I found my old entry.
What I recall is have a 3 foot length of rubber fuel line available. Disconnect the fuel hose from the genset at the fuel pump. Attach the new line to genset and drop the line into a container of one part SeaFoam to eight parts gasoline and run genset for 20 mins with a load. When empty re-attatch the fuel line and test genset with load.
I put in 50/50 mix and made lotsa smoke and stalled the genset. Too much SeaFoam. Re-attatched the fuel lines and ran the mixture out...still smoking. Now it runs much better, smoother and starts instantly whether still or while driving. This would mean my fuel was aging in the genset carb, and/or the carb had deposits that SeaFoam dissolved...which is its purpose. However if you have nasty clogging chemicals may not work and removal/repair of carb is the only solution...something I have to do on wife's mtcyl soon as she doesn't ride it enough and one of the carbs is clogged requiring removal.
Since you've already dropped the genset maybe now would be the time to do thorough servicing of the unit. Carb cleaning, slip-ring cleaning, etc. since you're past the hard part (removal).
I run the genset every month for an hour...sometimes that is insufficient with aging gas...but as we are gone 6 months/year I don't always do it. Most of the time it only runs while traveling.
What was your genset doing that prompted this latest action? Oh, I jus' read your blog...nevermind.
EDIT: Here's a thread I recognized...
Looks like you're gonna get to the bottom of it all soon!